Soak gelatin in cold water; set aside.,In saucepan, dissolve cornstarch in 1/4 cup cold milk.,______,Gradually add hot mixture to eggs, stirring well.,Return egg mixture to saucepan; cook and stir until thickened (do not boil).,Remove from heat.,Add gelatin, stirring until dissolved.,Blend in peanut butter.,Chill until mixture begins to thicken.,Fold in whipped topping.,Pour half of the filling into pie shell.,Add bananas; top with remaining filling.,Garnish with additional whipped topping rosettes, if desired.